Why wont my car start?

JERMAINE_27604

1989 MERCURY MARQUIS

200,000 MILES

Ive changed 1:spark plugs
2:wires
3:ignition control module
4:fuel filter
5:ignition coil
6:rotor button
7:cap
and still wont start but it will turn over. What do u think the problem could be. While looking under the hood it seems as one of the fuel injectors is loose. Could this be thee issue? Starter fluid wont make it crank either.